MethodParameters class file format change

David Holmes david.holmes at
Sat Jan 26 07:52:20 UTC 2013


These situations are historically known as Flag Days and they require 
careful management.

I don't know exactly what has to be done but the way to approach this is 
to modify the VM to be prepared to handle both the old format and the 
new. Then after it has reached TL/jdk&langtools update jdk/langtools to 
start using the new format. Then if needs be once everything is in sync 
you can remove the hotspot code that handles the old format. (I assume 
that both old and new format are new with regard class version 52?) That 
way nothing breaks.

There must already be tests for this new feature else you would be 
pushing untested code, so you would break these tests while your changes 
sync up.


On 26/01/2013 3:53 AM, Eric McCorkle wrote:
> I don't think anyone is using MethodParameters at this point, but I want
> to post this just to be sure.
> The latest version of the spec alters the class file format of
> MethodParameters attributes.
> The latest version can be found here:
> I will be committing patches to tl and hsx which update hotspot and the
> langtools tools to reflect this change.  However, this will take some
> time to propagate, and may affect anyone using this feature (most
> likely, to write tests).
> Apologies for any inconvenience,
> Eric

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